The present invention relates to drill bits for drills, especially for drills of the type used for roof drilling in mines.
Drills of that type are used for drilling holes in mine roofs for the purpose of installing roof bolts, for example. Attention is directed to U.S. Pat. No. 4,313,506 for a disclosure of such a drill.
In general, a drill of that type includes a hollow shank having an interior axial bore which is open axially rearwardly. A lateral opening extends through the shank and communicates with a forward end of the bore. At its front end the shank includes a radial slot in which a plate-like cutter insert or bit is fastened, usually by brazing. The insert includes a pair of cutting edges disposed ahead of two compression faces defined by the shank.
During a drilling operation, cuttings from the insert travel along the compression faces and are acted on by those faces so as to be progressively reduced to a dust-like consistency. The dust-like material travels into the lateral opening and then rearwardly through the bore.
When the insert becomes worn and requires resharpening or replacement, it is necessary to break the braze connection between the shank and the insert in order to be able to remove the insert.
It will be desirable to be able to eliminate the time and expense involved in braking a braze connection in order to remove the bit.